Regulating means



L. F. HOFFMAN REGULA'I'ING MEANS Filed May 15, 1922 2 Sheets-Sheet 1 F/Gil- Jan, 20, 1925.

L. F. HOFFMAN REGULATING MEANS l n y 1922 2 Sheets-Sheet 2 7 I NV EN TOR.

A TTORNE Y.

Patented Jan. 20, 1925.

UNITED STATES PATENT OFFICE.

LEON F. HOFFMAN, OF FRANKLIN, PENNSYLVANIA, ASSIG-NOR TO CHICAGO PNEU- HATIC TOOL COMPANY, OF NEW YORK, N. Y., A CORPORATION OF NEW JERSEY.

BEGULATING MEANS.

Application filed May 15,

To all whom it may concern:

Be it known that I, LEON F. HOFFMAN, a citizen of the United States, residing at Franklin, in the county of Venango and State of Pennsylvania, have invented oer-- tain new and useful Improvements in Regulating Means, of which the following is a specification.

The present invention relatea'to'apparatue for supplying fluid under pressure,and more particularly to means for controlling the and unloading of the compressor I loading and the throttling ofits driving jen 'e.

One of the objects'of the 'inventwmis'to provide control arrangement' forfapparatus of the type described having-n complicated parts and few connections 'daptedi'ffor selective operation. Another if object" to control the compressor independently gt: its

engine or alternatively to provide {automatic I control 1n response tolrecerver ressuregfor c ation of the elements of my improved regulating" device. I a

Fig. 2 is a side elevation, partly in section showing the main portion of my improved regulatmg, means.

Fig. 3 1s a section of theupper end of the air release valve.

Fig. 4 is a longitudinal section of the three way valve shown in Fig.2, with its plug or stopturned to a diflerent position.

'. F1 5 is an inverted viewof-thedisc of a di erential bly-pass'valve employed in my" im roved regu atmg device.

e construction shown in is substantially as follows: I

The air compressor is supplied with an suitable form of unloader as The 'thrott e 2 of the engine issupplied with an actuative device 3. Air under pressure is sup lied for the of actuating said unloa er 1 and sai device 3 byseparate conduits or .escape around said drawings 1922. Serial No. 561,193.

pipes 17 and 18 respectively from pipe 6 which communicates with the air in the receiver (not shown) into which said compressor is dischar ed. Suitable manual means such as a va vs 22 is provided for controlling the passage of fluid under pres sure to the unloader valve 1, while an automatic air release valve 4 controls the passage of fluid t0 the throttle actuating device 3.

The automatic control valve 4 has a chamber 5 in constant communication with suppipe 6, the lower end of said chamber y being closed by means of a yieldable air releasingvalve 1.,which normally prevents the escape of air from said chamber. Said -valve 7-. is yieldably .retained in its closed position by means of a compression spring 8, the degree ofcompression of which may be regulated by. the screw 9;. said screw is tubular and provided throughout its full length with a hole 10 for the. reception of the plunger or stem 11; the'plun er is free to move longitudinally and its ower end fits loosely within said hole 10, and any air which enters the spring chamber 12 may said stem through hole. When air in the receiver aforesaid reaches a certain predetermined degree of pressure, said valve 7 is forced downward to the posit1on shown in Fig. 3 and its lower face seats upon the seat 13, thus permitting the release 0 air through the small ports 14- into the annular chamber. l5.;;the;.air thus released passes into the pipe18 and to said'throttle.

actuator 3. When receiver pressure has become reduced, valve 7 is returned by said s ring 8 to its seat, as in 'Fig. 2 and the alr which has served to actuate said actuator 3 returnsthroughthe pipe 16 and vents to atmosphere through the hole 10.

Coordinated regulation of both the throttle actuating device 3 andthe unloader E1 in response to pressure fluid admitted and exhausted by automatic control valve 4 is efl'ected by theprovision of a by-pass connection 18 extending from conduit 18 at a point boy conduit 1 joining the latter preferably through'its manual control valve 22/ This arrangement permits manual control of fluid into and out of conduit 17, for which urpose valve 22 has a plug 23 with a t ree way opening, as illustrated in Fi 2 and 4, operated by a handle 24:. Wit valve 22 dlsposed as shown in Fig. 2, control of both 0nd automatic control valve 4 to the engine throttle 2 and the compressor unloader 1 is entirely automatic in response to the operation of the air release valve 4 a differential passage of fluid in by-pass 18 in opposite directions. Such means may take the form of an ordinary check valve 19, which is modified by providing the seating face of its disc 20see Fig. 5with small grooves 21 (or in any other way modifying said seating face) so that it will not wholly check the passage of air inthereturn direction, as the normal check valve would do, but will permit air to return very slowl therethrough. With the pipe 17, whic communicates with said- .unloader, thus equipped, it will be readily understood that air passes freely tov the unloader but vents back and out of, the same very slowly thus causing saidunloader to lag in its retraction from ts unloading position. At the same time air vents back from the actuator 53 freely and permits the fuel throttle to open immediately so that the engine will resume its normal speed before the load is taken up. From the above it will be clear that the manual control valve 22 in the conduit 17 extending to the unloader valve provides for selective control of the compressor either coordinately with the throttle device of the engine by receiver air automatically released by valve 4 (the engine being arranged to speed up before the load is applied) when valve 22 is positioned as-shown in Fig. 2,

or independentlviefctliathro tledevice by" ainahitteddirectly from the receiver when valve 22 is positioned as showni'n Fig. 4. Thus is provided a simple and convenient control arrangement w ereby the engine may be operated without load whenever desired, as to permit it to warm up before work is started.

I claim the following:

1. In combination, an air compressor havin an unloader valve, a driving engine for said compressor havin separate conduits leadmg 'to said unloader a throttling device,

and to said device from the motive fluid supply for actuating the same, an automatic control device in said throttle conduit responsive to Variation in the pressure of the motive fluid supply, a by-pass from said throttle conduit at a point beyond said control device to said unloader conduit, and means selectively to connect said unloader conduit with the motive fluid supply or with said by-pass. result suitable means are provided for causing 2. In combination, an air compressor having an unloader valve, a driving engine for said compressor having a throttling device, separate conduits leading to said unloader and to said device from the motive fluid supply'for actuating the same, an automatic control device in said throttle conduit responsiye ,to variation in the pressure of the motive fluid supply, a bypass from said throttle conduit at a point beyond said control device to said unloader conduit, said by-pass being constructed and arranged to pass motive fluid freely toward said un loader but to resist its passage in the opposite direction, and manually controlled means for selectively connecting said unloader conduit directly with the motive fluid supply or indirectly with the latter through said by-pass and automatic control device.

3. In combination, an ai'r'compressor having an unloader valve, a driving engine for said compressor having a throttling device, separate conduits leading to said unloader and to said device from the motive fluid supply for actuating the same, an automatic control device in said throttle conduit responsive to variation in the pressure of the motive fluid supply, a by-pass from said throttle conduit at a point beyond said control device to said unloader conduit, an im- Bi jiq tlf Seated check valve in said by-pass permitting free passage of motive fluid toward said unloader, and a manual control valve for selectively connecting said unloader conduit directly with the motive fluid supply or indirectly with the latter through said by-pass and automatic control device.

In testimony whereof I afiix my signature in presence of two witnesses.

LEON F. HOFFMAN. Witnesses R. DuDOR WORTH, R. P. Cowm. 

